WASHINGTON, D.C. ― A group of six high-profile American experts recommended in a letter to President Donald Trump on June 28 that he send a high-level presidential envoy to North Korea to jump-start talks in good faith and begin informal bilateral talks ― with no preconditions ― to explore options for more formal negotiations.

The prominent group included former secretary of defense William Perry (the author of the Perry Report on North Korea in 1999), former secretary of state George Shultz (during the Reagan administration), Robert Gallucci (the negotiator of the Agreed Frameworks in 1994), Siegfried Hecker (a world-renowned nuclear expert now with Stanford University), Richard Lugar (a retired chairman of the Senate Foreign Relations Committee) and Bill Richardson (a former U.N. ambassador and governor of New Mexico).

"Talking is not a reward or a concession to Pyongyang and should not be construed as signaling acceptance of a nuclear-armed North Korea," their joint letter to the President said. The authors also wrote: "Kim Jong-un is not irrational … the primary danger is a miscalculation or mistake that could lead to war."

According to the authors, the U.S. should make clear that it does not have hostile intentions toward North Korea and it wants to explore a peaceful path forward. They were hoping that Pyongyang then would announce a freeze on tests of ballistic missiles and nuclear weapons. The initial goal of the talks would be limited to "reduce tensions and cap North Korea's arsenal."

They also warned that there is no guarantee that diplomacy will work. But, "there are no good military options, and a North Korean response to a U.S. attack could devastate South Korea and Japan," according to the letter.

Without a diplomatic effort to stop Pyongyang's progress in missile and nuclear development, the renowned experts have "little doubt that the North will develop a long-range missile capable of carrying a nuclear warhead to the United States."

They agree that sanctions alone will not resolve the North Korean issue, and they believe: "Today there is a window of opportunity to stop these programs," perhaps through a good mixture of pressure and engagement.

A courtesy copy of their letter was sent to Secretary of State Rex Tillerson.